KISSIMMEE — For Osceola County and the shopping centers along U.S. Highway 192, oversupply may be the price of prosperity.

By next week, half a dozen malls ranging in size from 90,000 square feet to more than 300,000 square feet will have opened within a year along U.S. 192 in Kissimmee, battling each other for not only for shoppers but also tenants.

Mill Creek has suffered its share of casualties; a bookstore and a liquor store moved from Mill Creek to Kissimmee Square mall across the street.

While the new shopping centers have set off a scramble for smaller tenants, one mall manager in the county says the advent of the new malls does not necessarily mean the demise of the older ones.

''The big boys will knock them down in the pecking order,'' said John MacDonald, general manager of Maingate Outlet Mall on west U.S. 192.

''The older-center owner will have to rework and release to maintain a position, maybe not his position previously, but a position,'' he said.

''It's been going on for 20 years,'' he said. ''When you get an area that looks hot, as Osceola did 18 months ago, . . . everybody wants to jump on a hot area. And the people that hurt are the older, established strip centers. Those are the areas that always hurt -- for about two years.''

After those two years, he said, either the older centers are sold to new owners who invest in major improvements or the owners make improvements themselves. Or they shut down.

At two of Kissimmee's older shopping centers, that process already has begun.

Last month the Town Corral shopping center was purchased by a New Jersey real estate partnership that has announced plans to spend $250,000 to rework the facade of the 20-year-old shopping center at Bermuda Avenue and Vine Street.

''We are going to give it a complete facelift,'' said Chris Quidore, a real estate analyst with Bermuda Avenue Shopping Center Associates, the partnership that bought the center.

''Obviously, we know it's been neglected,'' he said. ''We want to bring it back.'' Those improvements will make the 20,000 square feet of vacant space in the 80,000-square-foot complex more marketable, Quidore said.

Mill Creek Mall, which has lost two tenants to the Kissimmee Square, is following the same tactic. Schwab said the center will undergo a $200,000 makeover, including interior renovations and exterior improvements such as new porticos. Those improvements would follow about $30,000 the company already has spent to upgrade its parking lot.

''We'll probably hold off until after the first of the year,'' she said. ''We're looking at it as important to the center to maintain the tenants and keep us competitive.'' About 80 percent of the mall's 113,000 square feet of space is now rented, she said.

The biggest of the big boys who are going to disrupt the county's shopping- mall pecking order is Osceola Square Mall. Unlike the area's other retail developments, most of which are variations of the strip-center format, Osceola Square, at 340,000 square feet, is the county's largest.

The center features long, broad concourses with high, skylighted ceilings. An officer of the mall's exclusive leasing agent said that, although the site is on U.S. 192, the company is targeting local residents.

''We didn't build that mall strictly for the tourists,'' said Gary Martin, president of Commercial Site Selectors, Maitland. ''The local tenants at Osceola Square Mall are not aimed at the tourist, they're aimed at the typical local shopper.''

Since the complex opened last month, Martin said, about 60 percent of its space is leased. He said he expects the rest to be contracted by spring. The leasing will be made easier when all the mall's anchors are ready, he said.

''Once we open that north-south corridor, it will begin to crank,'' he said. ''Morrison's Cafeteria will pull people in off that road.''

Maingate, Osceola's other big mall, may be less well-known, at least among the local population. The shoping center, on western U.S. 192, relies almost entirely on tourist trade, MacDonald said. The 271,000 square-foot mall is about 70 percent leased, he said -- somewhat behind expectations.

Because of its isolated location in relation to residential areas, Maingate uses a factory-outlet approach and a marketplace theme to attract tourists.

''We're not typical,'' MacDonald said. ''We're not a Florida Mall,'' he said, referring to the large shopping center in south Orlando, ''and we're not Osceola Square Mall. We're a factory outlet with festive retail.''